Osteotomies of the knee are an important technique for treating knee osteoarthritis. In essence, knee osteotomies adjust the geometry of the knee joint so as to transfer weight bearing load from arthritic portions of the joint to the relatively unaffected portions of the joint.
Most knee osteotomies are designed to modify the geometry of the upper tibia, so as to adjust the manner in which the tibia engages the femur and hence the locations at which the load is transferred across the joint.
There are essentially two ways in which to adjust the orientation of the tibia: (i) the closed wedge technique; and (ii) the open wedge technique.
With the closed wedge technique, a wedge of bone is removed from the tibia, and the portions on either side of the resulting gap are brought together, whereby to reorient the tibial plateau and hence adjust the manner in which the tibia engages the femur.
With the open wedge technique, a cut is made into the tibia, the portions on either side of the cut are moved apart so as to form a wedge-like opening in the bone, and then the bone is secured in this position (e.g., by screwing metal plates to the bone or by inserting a wedge-shaped implant into the opening in the bone), whereby to reorient the tibial plateau and hence adjust the manner in which the tibia engages the femur.
While both closed wedge osteotomies and open wedge osteotomies provide substantial benefits to the patient, they are procedurally challenging to the surgeon. Among other things, with respect to open wedge osteotomies, it can be difficult to form the wedge-like opening in the bone with the necessary precision and with minimum trauma to the surrounding tissue.
The present invention is directed to open wedge osteotomies, and to a new method and apparatus for forming the wedge-like opening in the tibia.